A ferrule for a multi-connector, which is installed at the end of a plurality of optical fibers and is used for connection between the optical fibers, is molded using a thermosetting resin or a thermoplastic resin.
For example, a ferrule 1 shown in FIG. 8 is provided with two alignment pin holes 1a in which alignment pins for positioning with respect to another ferrule of the same construction are inserted, and two fiber holes 1c which are formed at a predetermined interval between the alignment pin holes 1a and are open to a ferrule end face 1b so that optical fibers are inserted therein. As shown in FIG. 9, the ferrule 1 is also provided with a boot insertion hole 1d which is open to a rear end face, and an adhesive agent inserting window 1e which is formed at a substantially central portion perpendicularly to the boot insertion hole id and is open to a top face of the ferrule 1. In this construction, the ferrule 1 is formed with a fiber guide hole 1f located between the fiber hole 1c and the adhesive agent inserting window 1e, and a U-shaped groove 1g located adjacent to the fiber guide hole 1f. 
Therefore, the ferrule 1 is assembled into a multi-connector in the following way: An optical fiber, for example, an optical ribbon fiber with fibers separated is inserted through the boot insertion hole 1d, and the optical fibers are inserted into the fiber holes 1c through the U-shaped grooves 1g and the fiber guide holes 1f. Then, an adhesive agent is poured through the adhesive agent inserting window 1e to fix the optical fibers. The extending portion of the optical ribbon fiber is protected by a boot inserted into the rear part of the ferrule 1.